scholarly journals Fractional-Order Control of a Micrometric Linear Axis

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Luca Bruzzone ◽  
Pietro Fanghella
Keyword(s):  
Fractional Order ◽  
Position Control ◽  
Tracking Error ◽  
Transient State ◽  
Step Response ◽  
Controlled System ◽  
Fractional Order Control ◽  
Control Scheme ◽  
Derivative Term ◽  
Pole Location

This paper discusses the application of a particular fractional-order control scheme, the PDD1/2, to the position control of a micrometric linear axis. The PDD1/2scheme derives from the classical PD scheme with the introduction of the half-derivative term. The PD and PDD1/2schemes are compared by adopting a nondimensional approach for the sake of generality. The linear model of the closed-loop system is discussed by analysing the pole location in theσ-plane. Then, different combinations of the derivative and half-derivative terms, characterized by the same settling energy in the step response, are experimentally compared in the real mechatronic application, with nonnegligible friction effects and a position set point with trapezoidal speed law. The experimental results are coherent with the nonlinear model of the controlled system and confirm that the introduction of the half-derivative term is an interesting option for reducing the tracking error in the transient state.

scholarly journals Fractional-Order PII1/2DD1/2 Control: Theoretical Aspects and Application to a Mechatronic Axis

2021 ◽  
Vol 11 (8) ◽  
pp. 3631
Author(s):  
Luca Bruzzone ◽  
Mario Baggetta ◽  
Pietro Fanghella
Keyword(s):  
Fractional Order ◽  
Position Control ◽  
Tracking Error ◽  
Experimental Tests ◽  
Maximum Torque ◽  
Control Effort ◽  
Tuning Method ◽  
Alternative Approach ◽  
Remarkable Reduction ◽  
Distributed Order

Fractional Calculus is usually applied to control systems by means of the well-known PIlDm scheme, which adopts integral and derivative components of non-integer orders λ and µ. An alternative approach is to add equally distributed fractional-order terms to the PID scheme instead of replacing the integer-order terms (Distributed Order PID, DOPID). This work analyzes the properties of the DOPID scheme with five terms, that is the PII1/2DD1/2 (the half-integral and the half-derivative components are added to the classical PID). The frequency domain responses of the PID, PIlDm and PII1/2DD1/2 controllers are compared, then stability features of the PII1/2DD1/2 controller are discussed. A Bode plot-based tuning method for the PII1/2DD1/2 controller is proposed and then applied to the position control of a mechatronic axis. The closed-loop behaviours of PID and PII1/2DD1/2 are compared by simulation and by experimental tests. The results show that the PII1/2DD1/2 scheme with the proposed tuning criterium allows remarkable reduction in the position error with respect to the PID, with a similar control effort and maximum torque. For the considered mechatronic axis and trapezoidal speed law, the reduction in maximum tracking error is −71% and the reduction in mean tracking error is −77%, in correspondence to a limited increase in maximum torque (+5%) and in control effort (+4%).

Neural network–based sliding-mode control of a tendon sheath–actuated compliant rescue manipulator

2019 ◽  
Vol 233 (8) ◽  
pp. 1055-1066 ◽  
Author(s):  
Qingcong Wu ◽  
Xingsong Wang ◽  
Bai Chen ◽  
Hongtao Wu
Keyword(s):  
Neural Network ◽  
Sliding Mode Control ◽  
Position Control ◽  
Sliding Mode ◽  
Radial Basis Function Network ◽  
Tendon Sheath ◽  
Step Response ◽  
Mode Control ◽  
Control Scheme ◽  
Modeling Uncertainties

The novel contribution of this article is to propose a neural network–based sliding-mode control strategy for improving the position-control performance of a tendon sheath–actuated compliant rescue manipulator. Structural design of a rescue robot with slender and compliant mechanical structure is introduced. The developed robot is capable of drilling into the narrow space under debris and accommodating complicated configuration in ruins. Dynamics modeling and parameters identification of a compliant gripper with flexible tendon sheath transmission are researched and discussed. Moreover, the neural network–based sliding-mode control scheme developed based on radial basis function network is proposed to improve the position-control accuracy of the gripper with modeling uncertainties and external disturbances. The stability of the proposed control system is demonstrated using Lyapunov stability theory. Further experimental investigation including trajectory-tracking experiments and step-response experiments are conducted to confirm the effectiveness of the proposed neural network–based sliding-mode control scheme. Experimental results show that the proposed neural network–based sliding-mode control scheme is superior to cascaded proportional–integral–derivative controller and conventional sliding-mode controller in position-control application.

scholarly journals Robust position-based impedance control of lightweight single-link flexible robots interacting with the unknown environment via a fractional-order sliding mode controller

Robotica ◽  
2018 ◽  
Vol 36 (12) ◽  
pp. 1920-1942 ◽  
Author(s):  
Ali Fayazi ◽  
Naser Pariz ◽  
Ali Karimpour ◽  
Seyed Hassan Hosseinnia
Keyword(s):  
Fractional Order ◽  
Position Control ◽  
Sliding Mode ◽  
Impedance Control ◽  
Lyapunov Theory ◽  
Reference Trajectory ◽  
Constrained Motion ◽  
Unknown Environment ◽  
Control Scheme ◽  
Single Link

SUMMARYThis paper presents a fractional-order sliding mode control scheme equipped with a disturbance observer for robust impedance control of a single-link flexible robot arm when it comes into contact with an unknown environment. In this research, the impedance control problem is studied for both unconstrained and constrained maneuvers. The proposed control strategy is robust with respect to the changes of the environment parameters (such as stiffness and damping coefficient), the unknown Coulomb friction disturbances, payload, and viscous friction variations. The proposed control scheme is also valid for both unconstrained and constrained motions. Our novel approach automatically switches from the free to the constrained motion mode using a simple algorithm of contact detection. In this regard, an impedance control scheme is proposed with the inner loop position control. This means that in the free motion, the applied force to the environment is zero and the reference trajectory for the inner loop position control is the desired trajectory. However, in the constrained motion the reference trajectory for the inner loop is determined by the desired impedance dynamics. Stability of the closed loop control system is proved by Lyapunov theory. Several numerical simulations are carried out to indicate the capability and the effectiveness of the proposed control scheme.

scholarly journals Joint Position Control Based on Fractional-Order PD and PI Controllers for the Arm of the Humanoid Robot TEO

2019 ◽  
Vol 16 (06) ◽  
pp. 1950042
Author(s):  
Jorge Muñoz ◽  
Concepción A. Monje ◽  
Santiago Martínez de la Casa ◽  
Carlos Balaguer
Keyword(s):  
Fractional Order ◽  
Elbow Joint ◽  
Humanoid Robot ◽  
Position Control ◽  
Joint Position ◽  
Robust Performance ◽  
Tuning Method ◽  
Control Scheme ◽  
Pi Controllers ◽  
Humanoid Arm

This paper presents a control scheme for the humanoid robot TEO’s elbow joint based on a novel tuning method for fractional-order PD and PI controllers. Due to the graphical nature of the proposed method, a few basic operations are enough to tune the controllers, offering very competitive results compared to classic methods. The experiments show a robust performance of the system to mass changes at the tip of the humanoid arm.

Zero Phase Robust Control of XY Table Linear Servo System

2013 ◽  
Vol 419 ◽  
pp. 713-717
Author(s):  
Xi Mei Zhao ◽  
Ming Ming Jiang ◽  
Hong Yi Li ◽  
Hao Liu
Keyword(s):  
Disturbance Observer ◽  
Position Control ◽  
Control Method ◽  
Phase Error ◽  
Tracking Error ◽  
Servo System ◽  
Direct Drive ◽  
Tracking Accuracy ◽  
Control Scheme ◽  
Zero Phase

For direct drive XY table servo system, position control is designed. Considering the error which is caused by the disturbance of the system, friction factor and so on. The control method combing the zero phase error tracking controller (ZPETC) with the disturbance observer (DOB) is adopted. The system tracking error is reduced by adopting ZPETC, and through influences of disturbance to the system is diminished by the disturbance observer. Thus the tracking accuracy and robustness of the system are improved. Simulation results show that this control scheme is effective. It can obviously improve the accuracy of the system.

scholarly journals A Look-Up Table Based Fractional Order Composite Controller Synthesis Method for the PMSM Speed Servo System

2022 ◽  
Vol 6 (1) ◽  
pp. 47
Author(s):  
Weijia Zheng ◽  
Runquan Huang ◽  
Ying Luo ◽  
YangQuan Chen ◽  
Xiaohong Wang ◽  
...  
Keyword(s):  
Fractional Order ◽  
Synthesis Method ◽  
Differential Evolution Algorithm ◽  
Servo System ◽  
Step Response ◽  
Parametric Uncertainties ◽  
Composite Control ◽  
Look Up Table ◽  
Control Scheme ◽  
Composite Control Scheme

Considering the performance requirements in actual applications, a look-up table based fractional order composite control scheme for the permanent magnet synchronous motor speed servo system is proposed. Firstly, an extended state observer based compensation scheme was adopted to suppress the motor parametric uncertainties and convert the speed servo plant into a double-integrator model. Then, a fractional order proportional-derivative (PDμ) controller was adopted as the speed controller to provide the optimal step response performance for the servo system. A universal look-up table was established to estimate the derivative order of the PDμ controller, according to the optimal samples collected by an improved differential evolution algorithm. With the look-up table, the optimal PDμ controller can be tuned analytically. Simulation and experimental results show that the servo system using the composite control scheme can achieve optimal tracking performance and has robustness to the motor parametric uncertainties and disturbance torques.

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